Permanent well completion apparatus



Feb. 12, 1957 w. J. BIELSTEIN PERMANENT WELL COMPLETIQN APPARATUS Filed sept. 7, 1954 6 Sheets-Sheet l n UML lll Mtn... 1 l,...

Wa /er d. /e/J e/n INVENToR /lORA/E l u. Ema ....vl( 11,/1

, Feb. l2, 1957 w. J. BIELSTEIN PERMANENT NELL COMPLETION APEAEATUS 6 .Sheets-Sheet 2 Filed Sept. 7, 1954 IMI/ENTOR.

'ATTO /v Feb. 12, 1957 w. J. BlELsTElN 2,781,098

PERMANENT wsu. COMPLETION APPARATUS 6 Sheets-Sheet 3 Filed Sept. 7, 1954 Wa/Zer d. Efe/J en? INVENTOR. Y

Feb. 12, 1957 W. J. BIELSTEIN PERMANENT .WELL COMPLETION APPARATUS Filed Sept. '7, 1954 6 Sheets-Sheet 4 l/Va /er d.

. INVENTOR.

Feb. 12, 1957 Filed Sept. '7, 195! /l/l//lll/ W. J. BIELSTEIN PERMANENT WELL COMPLETION APPARATUS 6 shee'ts-sheet 5 Feb. 12, 1957 w. J. BIELSTEIN )2,781,098

PERMANENT WELL COMPLETION APPARATUS l I Filed sept. 7. 1954 -e sheets-sheet e l FIG. l2.

l JNVENTQIL Wal/er' J. B/'e/sfen,

A 7', TORNEK United Lf 2,781,098- PERMANENT WELL corvrPLETroN APPARATUS Walter J. Bielstein, Corpus Christi, Tex., assigiior, by mesne assignments; to Esso Research and Engineering The present invention is directed to a method and apparatus for completing and treating a well. More particularly, the invention is directed to a method and apparatus for c or'npletingV a well below the open end ota tubing. In its more specific aspects, the invention is Idirected to method and apparatus wherein a tubing is permanently arranged in a well casing.

The presentinvention may be briey described as a method for treating a cased well having a tubing per-V manently arranged in the cased well withthe vlower open end of the tubing arranged at a level above a'plur'ality of hydrocarbon productive strata. In the present in; vention the casing is perforated in the rst.- oftheV hydrocarbon productive strata following' which the" lower open end of the tubing is closed.l Atreating`-liuid; Vsuch as fresh or salt water, is then' circulateddown the arrnulus between the tubing and casing-andalongthe length ofthe casing/below the tubing at least incontact withv the perforations. The treating liquid is then conducted to the tubingand iiows up the tubing. Thereafter, the lower end of the tubing is openedandY the wellV isf the'n produced up the tubing.

It is contemplated that the present inventionwill iii`-` volve the conducting of a treatingV fluid, such as a' low water loss iluid cement, down the tubing and spotting the fluid cementrin the region-ot the perforations-vintth'e rst strataunder'conditions'to seal the perforatiohs following which a washing liquid, suchY as fresh or: salt water,` will be circulated down the 'annulus to remove' excess fluidY cement from .the casing-following which the Washingliquid and uid cement'isconducted tothe tubing and liowed upwardly therein before theflower end of the tubing is opened and the casingperforatedv in-,a second hydrocarbon productive strata;

The perforating of the'casing inthe second hydrocar bonv productive strata may be performed by'lowering'a gun perforator through the open endofthe-'tubing' and firing. the gun through-the casing-in thesecond hydroi carbon productive strata.

It is contemplated in the practice Yof the'presentiri` vention that the cement may be4 allowed' to' lill the-perforations to form a lter'cake thereinto seal'theperfoi-ations, or aV body of cement may beV arranged in `the casing in contact with the perforations andpressureI applied tothe cementto squeeze same into'the perforations or into the strata to seal the perforations.

It is contemplated in' the method of the`pres`ent in# vention that a treating liquid, such vas iluidcement, acid, acid; gel, Vfresh or salt water, s uspensions'of solidsofoil and theflike maybeowed downthetubingt treat the well'or formation; SuchY treating operationsmayffin tetes atetttf clude washing ther Well to remove sand, cementingfop.-

erations, fracturing of the formation' through the .perforations,` treatment of a formation with acidor -wlth ac'id gel, 'or' forming' new perforations in ithe casing by ring a gun perforator in a clean liquid and the'likef- The-.present ir'iventioni` also 'comprises-apparatus `for i 2, conducting permanntwell completions wherein the'tubing string ispcrmanently arranged in the casing at a level above a plurality of hydrocarbon productive strata. This apparatus comprises a mandrel adapted to be connected to the lower open end of the tubing string having a passageway adapted to communicate with the tubing on connection thereto; A tubular member isv connected to the lower end of the mandrelon an axis otset frbm` the longitudinal axis of the tubing. The tubular member may be of a length sufficiently great to extend from the lower open end ofthe tubing to a level below the hydrocarbon productive strata or mayY extend'V to within the series o`r plurality ofl hydrocarbon productive strata. A packer assembly may be connected to the mandrel for closing on theA annulus between the tubing' and tlie casing; Arranged in the mandrel cti-axially with the longitudinal axis o'f thtubing-is 'ow directing means for directing ui'df flow from the tubing through the mandrel to the tubular member and from the 'ani nulus` to the packer assembly; A nipple is connected to the mandrel cci-axially' with longitudinal axis of' tli tubing and a retrievabiemeans, such asN a plu'gQis arranged inVV the nipple for opening-and closing the nipple." Thev nipple may" be' used to' direct fluid new' fronfr the tubin'glthrciigh the mandrel to` the tubular member.

The tubularj member may' be provided with aitrjak which extends substantially the length of the tubular member and the' nipple is' provided on its internalY surface with a* spiral indexing means for positionitigjan elongated carriage,V such as ar tubing gun` perjator; lowered through tn tubing* and" nipple:l on the track member. The'ilow directingcmeans'for directing yiuid owthrougli the mandrel and'th'ro'ghthe packer assembly Amay bea rotatablev polish'joint having allow passage arranged therein or may bea' retrievable plug provided with ow passages. The present'invention will be further illustrated by referenceE to the" drawing in which;

Figkl show'san arrangement of the apparatus ofl the present invention inY a cased and tubed well; Fig'. 2 isa sectional view taken along the lines 2 2 Ofig'al' Fig'. 3'is" a1 sectional view'taken along the lines'3"-3 of Fig. l; Fig. 4 is a sectional view showing a detail of the' ini de'xing means arid plug illustrated in Fig. 1; Fig.' 5 is a detailed sectionalview of the indexing means andjtrack member of Fig'. 1; Fig. 'sh'ows 'an' arrangement for connection to a g un carriage' for psitioiiin'gthev gn on the theVV track mem-- bef of Figi l;

Fig-7 is a crosssectional'view'of the apparatus Fig. 6;'V Y

Fig. 8 shows adetail ofthe device -of the presentinvention with a packerassembly; Fig. 9 is aview taken along the lines 949 of Fig. Sshowing thelow directing means;

F"gs l 0 and 10a show a modification of tus'ofFigS;

Fig. ll is a Asectional view -of a production plug also shown in Fig. 10a; andj Y t Fig. ll2 shows `a further modification of the apparatus of Fig. 8." v

ReerrngnQw Ato the drawing in which identical numer# als will be employed te designate identical parts, numeral 11 designates a well .casing which has been arranged in a well-bore .12, drilledirom the earthlssurface 1-3. The well casing 11 has been cementedin' place-with cement 14 and the-casingll hasbeen'perforatedtoform perfor-ae tions 15 through-'the'casing 11 and cementlto. penetrate a. hydrocarbon productive strata A which has been penetrated by the well 12 and from which production of hydrocarbons has 'been obtained.

A tubing string 16 has beenarranged in the casing 11 from the wellhead 17 and is provided with Christmas tree 18. The casing 11 has a conduit 19 controlled 'by casing annulus valve 20. The Christmas tree is provided with valves 18a and 1812. f Arranged on the lower end of the tubing 16 is a mandrel 21. This mandrel is provided with a passageway 22 which communicates with the interior of the tubing 16 and has connected to it on an axis offsetting the longitudinal axis of the tubing a tubular member 23 which has a track member 24 Iarranged on the exterior surface thereof extending'substantially the lengthrof thertubular member. Connected to themandrel 21 co-axially with the tubing 16 is a nipple 25 which is provided with -a spiral indexing means 26 which serves to position a gun perforator lowered through the tubing onto the track 24.

The tubing 16 is provided with a plurality of wire line gas-lift valve mandrels 27 which are arranged on the tubing 16 at vertically spaced apart intervals as is conventional to the art.

It is to be noted that the tubular member 23 extends from the lower open endv of the subing 16 to the lower end of the casing 11. It is possible to direct lluid through the tubing 16 and through passageway 22 in the mandrel 21 by providing in the nipple 25 a retrievable tubing plug 28 which serves to close the open end of the tubing 16 and to direct uid into the tubular member 23.

Referring now to Fig. 4, it will be seen that the mandrel 21 is connected to the lower end of the tubing 16 by mating threads 29 and the nipple 25 is connected to the mandrel 22 by mating threads 30. The tubular extension member 23 is also connected to the mandrel 21 by mating threads 31. It is to be noted that the plug 28 closes the nipple and directs ow from the tubing 16 by way of passageway 22 into the tubular member 23. Y

Referring now to Fig. 6, a tubing gun perforator 41 which may be provided with conventional 'bullets or shaped charges 42, has an upper housing 40 which is provided with slots 43 through which spherical followers 44 project to engage with the spiral or indexing means 26 in nipple 25. These spherical followers 44 are-,carried on rocker arms 45 which are arranged on a rocker arm pin 46, as shown. The rocker arms 45 are biased outwardly through slots 43 by biasing means such as coil springs 47. The gun perforator is designed to be run through tubing 16, out nipple 25, along track member 24 to a position for perforating casing 11.

Referring now to Fig. 8, set in the casing 11 is a packer assembly 61 having a mandrel 60 forming an integral part thereof. TheY packer assemblygl closes oiv the annulus 62 lbetween the tubing 16 and the casing'll. The packer assembly 61 is provided with bypass conduits 63 and 63a while the mandrel 60 hasa passageway 64 communicating with the extension member 23 which is connected to the mandrel 60 by mating threads 31.

Rotatably arranged in the mandrel 60 and packer assembly 61 is a polish joint 65 which is connected rigidly to the tubing 16 such as by welds 66. The tubing 16 has a'window or slot 67 therein which serves to communicate Referring nowlto Figs. l() and 10a, set in the casing 11v is a mandrel assembly 81 to which the extension member 23 is connected by mating threads 31. The mandrel assembly 81 is provided with packers 80 and 80a. The mandrel assembly 81 is also provided with a rst bypass conduit 82 opening into port 83 of tubing 16 and Vasecond bypass conduit 85 opening into port 86 of tubing 16. The mandrel 81 has a passageway 87 communicating with a port 88 in the tubing 16.

In Fig. l0 wire line ow directing means 89 is arranged in the tubing 16 for directing ow through rthe extension member 23. The wire line plug 89 is provided with a shing neck 90 and is provided with a central passageway 91 which has an opening 92 which communicates with the opening 88 and the passageway 87 allowing liuids to ow through the tubing 16, the passageway 91 and through the extension member 23. It will be noted with respect to Fig. 10 that the plug 89 is provided with sealing members `93 land 94.

In the embodiment of Figs. 10a and l1 the plug 89 has been replaced by a production plug provided with a fishing neck 101 which serves to close the flow through the bypasses 82 and 8S and through the passageways 87 and 91 allowing production from the well throughpassageway 102 and through openings 103.

The plug 100 is provided with seals 104 and 105 which serve to close off llow through the bypassing conduits and through the extension member.' The external shoulder 106 effectively closes the ilow between passageways 82 and 85.

The embodiment shown in Fig. l2 is similar to the embodiment yof Fig. 8 and operates substantially in the same manner as the embodiment shown in Fig.V 8. The embodiment of Fig. 12 dilers from Fig. 8 in the inclusion of a spiral indexing means 26 which positions a gun perforator lowered through the tubing onto the track 24.

The invention operates as follows:

It will be noted that the tubing 16 is arranged in casing 11V having the tubular member 23 connected thereto and made up with the tubing 16 as it is arranged in the casing. For purposes of this description it may be assumed that production from stra-ta A has reached a point where water and/or gas invasion has made the production of liquid hydrocarbons non-commercial and it is desirable to open up production in strata B which is separated from strata A by a non-productive strata, such as C, which may be shale or the like. Under these conditions, a clean Huid, such as salt water or the like, will be circulated down the annulus 62 following the direction vof the arrows and upwardly through the lower open end of the tubular member 23 and upwardly through the tubing 16 to the well head 17 and outwardly through the Christmas tree 18. This circulation is continued Vuntil the well is completely washed and the circulation of clean uid is terminated. A treating agent, such as cement, which may be a low water loss fluid cement, such as described by Salathiel in U. S. 2,482,459, or other low Water loss fluid cements available on the market may be used. This cement is owed downwardly through the tubing 16 and is directed into the extension member 23 by the wire line tubing plug 28 which has been placed in the nipple 25 before the circulation, as has been described, is initiated. The cement ows downwardly through the tubing and tubing extension and upwardly in the casing to the region of the perforations 15. This cement. may be allowed to till the perforations 15 and form a tilter cake or buttons therein as shown and indicated generally by the numeral 15a which serves to seal off the strata A. It maybe desirable, however, to spot a body of uid cement in the region of the perforations -15 and to impose pressure on the cement, such Yas with a Bradenhead squeeze, the technique of which is well known to the art. In any event, after the perforations 15y have been closed and sealed against uid intrusion fromV strata A, clean uid is circulated down the annulus 62 to washout the excess uid cement remaining in the casing 11. This washing duid and fluid cement is'directed up' the tubular member 23 and through the tubing 16 to the surface of the earth 13, through well head 17 and Christmas tree 18.

.onerose wire line with a suitable shing tool on the end of it to pull the plug 23 from the tubing 16. A tubing gun perforator, such as illustrated in Fig. 6, is then attached to the wire line and lowered through the tubing 16 and through the mandrel 21 into the nipple 25. The spiral followers engage with the spirals 26 which on continued lowering of the tubing gun d1. cause the tubing gun and the upper housing 4) to be positioned on the track 24, one of the spiral followers engaging with the .track 24 and positioning the gun. By virtue of positioning the gun perforator 40 on the -track 24, it is possible to perforate, the casing 11 in the strata sand or interval B which is hydrocarbon productive and also to perforate the casing 11 in the strata B inV a predetermined direction without damaging the tubular member 23. After the casing 11 has been perforated in the strata B, the tubing gun is pulled by means of a wire line and production is then had from :the strata B through the perforations 15b opened up therein. This seriesaof operations may be repeated for asV many producingl intervals orY strata as may be enf countered below the lower open end of the tubing 16'` In the apparatus ofY Figs. 8 and 9 wherein a packer assembly 61 is used, it is possibleY to direct the ow of iiuid` through the extension member 23- and through the packer assembly by rotating theY tubing 16 to allow communication between the passageways, 63. and 63a and between the tubing 16 and the extension member 23 utilizing the treating sequence of operations as described with respect to Fig. 1.

' The same result may be achievedA by cementing and circulating out with respect to Figs. 10a and 1l as described with respect to Fig. 1 and Figs. 8 and 9; in this latter instance the plug S9 being used when circulating and cementing and the. plug 190 beingrused when pro'- ducing.

As stated, the present invention isv susceptibleA to many well servicing operations and has considerable utility in that all operations may be conducted without requiring heavy-duty lifting equipment. In fact, the tubing is permanently set in the casing and completing and servicing operations are conducted by use of wire line tools as has been described or by simply rotating the tubing to achieve the desired circulation patterns which are required.

The invention may be used in fracturing formations, in acidizing operations, in washing forremoval of sand from casing and for gun perforating operations.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful andto secure by Letters Patent is: t

1. Permanent well completion apparatus which comprises, in combination, a mandrel adapted to be connected to the lower open end of a tubing string permanently arranged in a cased well at a level above a plurality of hydrocarbonproductive strata having` a passageway adapted to communicate with the tubing on connection thereto, a tubular member connected Ato the lower end of said mandrel on an axis o-set from the longitudinal axis` of the tubing, a nippleconnectedwto saidv mandrel co=axially with the longitudinal axis of the tubing, retrievable means in said nipple for opening and closing said nipple and adapted Vto direct fluid oW from the tubing through the mandrel to said tubular member, a track member on said tubular member extending substantially the length of said tubular member, and indexing means in said nipple for positioning a carriage lowered throughV said tubing and nipple on said track member.

2. Permanent well completion apparatus which comprises, in combination, a mandrel adapted to be connected to the lower open end of a tubing string permanently arranged in a cased well at a level above a plurality of hydrocarbon productive strata having a passageway adapted to communicate with the tubing on connection thereto, an

elongated-tubular member connected to the lower end of saidmandrel on an-A axis-oifset from the longitudinal axis of the tubing, a nipple connected to said mandrel' coaxially with the longitudinal axis' of the tubing, retrievable plug. means inA said nipple for'opening and closing said nipple and adapted to directfuid ow from' the tubing throughv the mandrel-to said tubular member, atrack member on said tubular member extending substantially the length of said tubular member, and a spiral indexing means in said nipple for positioning a carriage lowered through said tubing and nipple onsaid track member.

31. Permanent well completionapparatus which comprises, in'. combination, a mandrel adapted to be connected to the lower open end of a tubing string permanently arranged in a cased wellat alevel above a plurality of hydrocarbon productive stratahaving` a passageway adapted tofc'ommunicate with the tubing ou connection thereto, an elongated tubular member connected to the lower end of said mandrel onan axisoi-set from the longitudinal axis of the tubing, a. nipple connected to said mandrel coaxially with'the. longitudinal axis of the tubing, retrievable plug means ink said nipplefor opening and closing said nipple. and vadapted to direct fluid flow from the tubing throughthe mandrelto said tubular member, anY elongated carriage adapted to be lowered through saidrm'andrel and nipple, a track memberon said tubularmember extending substantially the length of saidtubular member and a spiral indexing means in said. nipple for positioning said carriage on said. track member- Y 4. Apparatus in accordance wit-h claim l5' in which the carriageisa gun perforaton 5; Permanent well completion apparatus which comprises, in combination, amandrel adapted to lbe connected Y tothe lower open end-ofa tubing string' permanently: arranged in acased` well a-talevel above a plurality-*of hydrocarbon productive strata having; a passageway adapted to communicatewith the tubingon connection'tliereto, a tubular member connected to the lower Vend. of said mandrel on an axis olf-set from the longitudinal axis` of the tubing, a packer assembly connected to said mandrel for closing ofi the annulus between. the tubing. andk casing, means arrangedfinsaid mandrel co-axially, with the 1ongitudinal axis of the tubing-.for directing uid flow from the tubingthrough the mandrel-to the ltubular member and from the annulus through the packer assembly, a nipple adapted to be connected to said mandrel co-axially with the longitudinal axis of the tubing,` retrievable` means in said nipple: for opening and closing. said nipple, a track member on said tubular member extendingvsubstantially the length of said tubularmember, and indexing means in said nipple for positioning a carriage lowered through said tubing and nipple on saidV track member.

6. Apparatus in accordance with claim 5 in which the flow directing means `isarotatable polishv joint'havinggow passages therein.

7. Apparatus Vin accordance rwith. claim 5- inwhich the ow directing'means in a retrievable plugV having-'flow passages therein.

8'. Permanent wellcompletionapparatus which cornprises,.in combination, amandrel adapted to be connected to the lower open end ofla tubingstring permanently arrangedin` a` cased 'well' at'a levelaboveatiplurality of hydrocarbon productive strata having a passageway adapted to communicate with the tubing on connection thereto, a tubular member connected to the lower end of said mandrel on an axis ott-set from the longitudinal axis of the tubing, a packer assembly connected to said mandrel for closing o5 the annulus between the tubing and casing, means arranged in said mandrel co-axially with the 1ongitudinal axis of the tubing for directing iluid flow from the tubing through the mandrel to the tubular member and from the annulus through the packer assembly, a nipple adapted to be connected to said mandrel co-axially with the longitudinal axis of the tubing, retrievable plug means in said nipple for opening and closing said nipple,'a track member on said tubular member extending substantially the length of said tubular member, and a spiral indexing means in said nipple for positioning a carriage lowered through said tubing and nipple on said track member.

9. Permanent well completion apparatus which comprises, in combination, a mandrel adapted to be connected to the lower open end of a tubing string permanently arranged in a cased well at a level above a plurality of hydrocarbon productive strata having a passageway adapted to communicate with the tubing on connection thereto, an elongated tubular member connected to the lower end of said mandrel on an axis of-set from the longitudinal axis of the tubing, a packer assembly connected to said mandrel for closing o the annulus between the tubing and casing, means arranged in said mandrel co-axially with the longitudinal axis of the tubing for directing uid ow from the tubing through the mandrel to the tubular member and from the 'annulus through the packer assembly, a nipple adapted to be connected to said mandrel co-axially with Vthe longitudinal axis of the tubing, retrievable plug means in said nipple for opening and closing said nipple, an elongated carriage adapted to be lowered Vthrough said mandrel and nipple, a track member on said tubular member extending substantially the length of said tubular member, and a spiral indexing means in said nipple for positioning said carriage lowered through said tubing and nipple on said track member.

l0. Apparatus in accordance'with claim 9 in which the carriage is a gun perforator.

11. Permanent well completion apparatus which comprises, in combination, a mandrel adapted to be connected to the lower open end of a tubing string permanently arranged in a cased wellrat a level above a plurality of hydrocarbon productive strata having a passageway adapted to communicate with the tubing on connection thereto, a packer assembly connected to said mandrel for closing ol the Vannulus between the tubing and casing, a tubular member connected to the lower end of said mandrel on an axis oi-set from the longitudinal axis of the tubing, a track member on said tubular member extending substantially the length of said tubularV member, means arranged in said mandrel co-axially with the longitudinal axis of the tubing for directing fluid ow from the tubing through the mandrel to said tubular member and from the annulus through said packing assembly, and means in said mandrel for positioning a carriage lowered throughsaid tubing and lmandrel on said track member for longitudinal movement thereon parallel to the longitudinal axis of said tubular member.

12. Permanent well completion apparatus which com' prises, in combination, a mandrel adapted toV be connected to the lower open end of a tubing string permanently arranged in a cased well at a level Vabove a plurality of hydrocarbon productive strata having a passageway adapted to communicate with the tubing on connection thereto and being provided with horizontally spaced apart openings in the lower end of the mandrel, a tubular member connected to one of said spaced apart openings on an axis off-set from the longitudinal axis of the tubing, retrievable means positioned in said other spacedn apart opening adapted `to permit and close 0E uid 4flow through said other opening and adapted to `direct Vfluid, flow from the tubing through the mandrel tosaid tubular member, a track member on said tubular member extending substantially thellength of said tn bular member, and means in said mandrel for positioning a carriage lowered through said tubing and mandrel on said track member.

13. Permanent well completion apparatus which comprises in combination a tubing string permanently arranged in a well casing at a level abovea plurality of hydrocarbon productive strata, means connected to the lower open end of said tubing string formed to provide a passageway adapted to uidly communicate with said tubing string, a tubular member connected to said passageway forming means on an axis olset from the longitudinal axis of said tubing string adapted to fluidly communicate with said passageway, a nipple connected to said passageway forming means coaxially with the longitudinal axis `of said tubing string adapted to uidly communicate with said passageway, retrievable means in said nipple for opening and closing said nipple and adapted to direct fluid flow from said tubing string through said passageway forming means to said tubular member,. a track member on said'tubular member extending substantially the length of said tubular member,` and indexing means in said nipple for positioning a carriage lowered through Said tubing and nippleron said track member. f

14. Apparatus in accordance with claim 13V in which the ow passageway forming means comprises a packer adapted to close oif the annulus between the tubingV string and the casing, said packer being provided Vwith means providing uid ow from the annulus through the packer and said retrievable means being adapted also to close and 4open said fluid ow providing means.

15. Apparatus in accordance with claim 13 in which the ow passageway forming means comprises apacker adapted to close the annulus between the tubing string and the casing. Y

16. Apparatus in accordance with claim 13 in which the flow passageway forming means comprises a mandrel provided with means for closing oi the annulus between the tubing string and the casing and with means Vprof viding fluid ow from the annulus through the Imandrel and in which said retrievable means 'is adapted also to close and open said fluid ow providing means.

References Cited in the tile of thisrpatent UNlTED STATES PATENTS Lynn Aug. 28, 1917 1,644,748 Schweiger Oct. l1, 1'927 2,176,375 McClinton y Oct. 17, 1939 2,403,987 Lewis `luly 16, 1946 2,649,916 Brown Aug. 25, 1953 2,718,264 Allen et al. Sept. 20, 1955 OTHER REFERENCES Petroleum World and Oil, May 28, 1953, page 34. Oil and Gas Journal, August 3, 1953, page 112. 

